President Donald Trump has decided to remove White House national security advisor H.R. McMaster from the administration, The Washington Post said on Thursday — though the White House subsequently denied there are changes coming to the National Security Council.

The Post said the president is "now comfortable" removing McMaster, but that he's taking his time on an announcement because he doesn't want to embarrass the Army lieutenant general, and he wants a smooth transition.

The Post cited five sources with knowledge of the president's plans. The Wall Street Journal subsequently confirmed the report, adding that timing of the move is unclear but could be months away.

If that decision is made official, McMaster would become second national security advisor to leave the job since Trump took office last year. He has had the task of advising a president who often tweets unfiltered thoughts about delicate national security situations such as North Korea's weapons program and the Iran nuclear deal.

The Trump administration pushed back on reports of an imminent departure. White House press secretary Sarah Sanders said on Twitter late Thursday that the president has a "good working relationship" with his national security advisor, and "there are no changes" at the National Security Council.

McMaster's departure would remove a knowledgeable foreign policy voice from a Trump inner circle that lacks many officials experienced in national security. Since taking the position, McMaster has faced criticism from some Trump supporters who have attacked him as a "globalist."

Trump differs with McMaster's take on Russia

McMaster drew Trump's ire last month by saying the evidence that Russia meddled in the 2016 U.S. election is "incontrovertible," following more than a dozen indictments from special counsel Robert Mueller's office. Trump lashed out at McMaster in a late-night Twitter post last month.

"General McMaster forgot to say that the results of the 2016 election were not impacted or changed by the Russians and that the only Collusion was between Russia and Crooked H, the DNC and the Dems. Remember the Dirty Dossier, Uranium, Speeches, Emails and the Podesta Company!" Trump wrote.

According to the Post, Trump has complained that McMaster's briefings were too lengthy and seemed irrelevant. The newspaper said possible candidates to fill the post include former U.S. ambassador to the United Nations John Bolton and National Security Council Chief of Staff Keith Kellogg.

The president's first national security advisor, Michael Flynn, got forced out in February 2017 after misleading White House officials about his contacts with the Russian ambassador to the U.S. He later pleaded guilty to lying to the FBI about those meetings.

Correction: This article has been updated to accurately reflect when President Donald Trump criticized White House national security advisor H.R. McMaster in a late-night Twitter post.